PROJECT SUMMARY Heavy alcohol use and dependence has become a major public health concern within America and across the globe with limited treatments currently available to those who seek them. Binge intake of alcohol is a significant risk factor to the development of dependence and that this form of intake leads to major health concerns that are a large part of the public financial burden that the we must face each year. Our lab, along with many others, have implicated the role of the extended amygdala in ethanol consumption. Of particular interest in this macrostructure is the central amygdala (CeA), which has itself been seen to play an imperative role in binge- like ethanol intake in animal models. Alterations of these GABAergic populations within the CeA modulate ethanol intake in rodents and research indicates that a subpopulation expresses the neuropeptide Y1 receptor (NPY1R). This receptor has protective effects against ethanol consumption. Work from our lab shows that there is a GABAergic and a NPY1R-expressing neuronal projection leading to the aversive learning area, the lateral habenula (LHb). This area sends glutamatergic projections into the rostromedial tegmental area which is responsible for shutting down ventral tegmental area (VTA) dopamine releases and causing an anti-reward effect. This proposal focuses on examining the role of NPY1R-expressing neurons in the CeA to LHb pathway in modulating binge-like ethanol consumption and to evaluate the cellular changes in signaling in these neurons stemming from binge-like ethanol consumption. Proposed experiments will use biochemical, chemogenetic, transgenic, electrophysiological and pharmacological approaches. The well- validated model of binge-like ethanol intake in rodents `drinking in the dark' (DID) will be used throughout these experiments. For Aim 1, I will use multiplexed designer receptor technology (viral injections of Cre-dependent KORD in CeA and VGAT1-promoter DREADD in RMTg) and cannulation in LHb, along with NPY1R-cre transgenic mice in the DID model to determine if silencing NPY1R-expressing neurons projecting to the LHb will attenuate binge-like ethanol drinking and associated blood ethanol concentrations (BECs) and whether simultaneous silencing of GABAergic neurons in the RMTg will mitigate this effect. For Aim 2, I will use chemogenetics as in Aim 1 with retrobead infusions into LHb (to prominently label NPY1R-expressing neurons projecting from the CeA to the LHb) along with the DID model and in vitro electrophysiological recordings to determine 1) if this population of neurons have a heightened baseline neuronal activity in animals that are exposure to one cycle of DID with ethanol versus those exposed to DID with water and whether these neurons also show a heightened sensitivity to acute ethanol-induced increases of neuronal activity compared to water counterparts, and 2) whether this population of neurons in animals exposed to ethanol have decreased activity in the NPY/NPY1R system as evidenced by decreased sensitivity of a NPY1R antagonist to alter electrophysiological activity. These results will provide new insight into the neurocircuitry driving binge drinking.